NORWALK - A Norwalk family is looking for the stranger it says saved it from death by carbon monoxide poisoning.

Tom Mackno says he was working on the furnace at the home he shares with his mother on Maurice Street back in June.

Later that day, he says they heard a knock on the door but ignored it. About 10 minutes later, they heard a loud crash and it was firefighters breaking in.

It turns out, a passerby spotted thick black smoke coming from the basement and called for help.

Firefighters say when they arrived, carbon monoxide levels were so high, the Macknos might have had only another 10 minutes to get out before the levels became fatal.